1. Field of the Invention
The present invention relates to IC testing, and particularly relates to a loop-back method of testing ICs.
2. Description of the Prior Art
The invention of the integrated circuit, or chip, was one of the most important developments in electronics. Integrated circuits (ICs) are present in almost all modern electrical devices from cellular phones to refrigerators. Communication systems, transport systems, manufacturing and computing all depend on the existence of ICs. Integrated circuits are also an integral part of modern transceivers.
Transceivers are electronic devices that have a combined receiver and transmitter. In general, a significant amount of circuitry is shared between the receiver and transmitter. As the receiving and transmitting parts of the transceiver still have some individual circuitry, it is possible for the receiving part to have functionality when the transmitting part does not (and vice versa). Therefore, to determine operability of an IC, both receiving and transmitting functions need to be tested.
In conventional systems, testing of transmission quality and receiving quality is performed separately. Please refer to FIG. 1. FIG. 1 is a diagram of a conventional test system 100 for testing transmitting operability of an IC. The test system 100 comprises: an HF RFID IC 150, comprising a digital processor 140, a transmitter 130 and a receiver 120; a loop antenna 160; and a high cost tester 170. The IC 150 will transmit a signal to the loop antenna 160, which then passes the signal to the high cost tester 170 for monitoring the waveform of the signal. The high cost tester 170 has to perform sophisticated analysis on the transmitted signal in order to determine operability of the HF RFID IC 150.
Please refer to FIG. 2. FIG. 2 is a diagram of a conventional test system 200 for testing receiving operability of an IC. Components having the same function as those shown in FIG. 1 are given the same numerals. The system 200 also includes a responder 270, which may be a tag or a near field communication (NFC) device, and can transmit data to the IC 150 directly (active mode) or respond to a command (passive mode). The IC 150 will receive, demodulate and decode the data from the responder 270, and if a bit error rate of the data is higher than certain thresholds, the chip will be determined to be a bad chip.
In both testing cases, high quality circuitry is required for confirming the accuracy of the IC. Therefore, the testing process is both time-consuming and expensive.